Effective Approach for Choosing, Designing, and Executing Permeation Grouting Treatments

Permeation grouting in granular soils is widely used as an improvement technique prior to the construction of large structures or for securing them. Owing to the minimal surface disruption it causes, this method is particularly suitable for applications in urbanized areas and for the rehabilitation of existing foundations. From an engineering perspective, careful design and execution are crucial to ensure the effectiveness of the treatment while also addressing cost efficiency and sustainability considerations. Nevertheless, the design of permeation grouting still relies predominantly on empirical methods and in situ experimental observations. This study proposes a new theoretical predictive model that leads to the derivation of injectability charts to support: (1) the design and optimization of the low-pressure injection process, fundamental for the permeation grouting, primarily in terms of flow rate, injection source spacing, grout type, and chemical composition; and (2) the interpretation of in situ test results required before treatment execution. Although simplified, the proposed design tool accounts for soil microstructure and hydraulic properties, operational constraints related to equipment, the need to minimize surface disturbance by controlling injection pressures, and the rheological behavior of grouts.